And I'm Audie Cornish. It's no secret that New Jersey Gov. Chris Christie has struggled with his weight. However, it was a secret when Christie had weight loss surgery on his stomach earlier this year. The governor confirmed today that he had an operation. Christie insists the decision was motivated by his family, not politics.

Christie insists the decision was motivated by his family, not politics. As NPR's Joe Rose reports, not everyone is convinced.

JOEL ROSE, BYLINE: Chris Christie is not afraid to laugh at himself, as he did during an appearance on the "Late Show with David Letterman," in February.

(SOUNDBITE OF TV SHOW, "LATE SHOW WITH DAVID LETTERMAN")

DAVID LETTERMAN: I've made jokes about you, not just one or two, not just ongoing here and there, intermittent, but...

(AUDIENCE LAUGHTER)

ROSE: Cut to Christie eating a doughnut.

GOV. CHRIS CHRISTIE: I didn't know this was going to be this long.

(AUDIENCE LAUGHTER)

ROSE: But Christie was not joking around today when he spoke to reporters about his decision to get lap-band stomach surgery three months ago.

CHRISTIE: I turned 50 years old, and it made me think, you know. It gave - I got confronted with, you know, your own mortality as you start to age.

ROSE: Christie, who was rumored to weigh somewhere between 300 and 350 pounds before the surgery, says he's lost about 40 pounds. Christie insists he made the decision because of his wife and four kids, not his political ambitions.

CHRISTIE: It's not a career issue, for me. It is a long-term health issue, for me. And that's the basis upon which I made the decision.

ROSE: But political observers suspect that's not the only reason.

PATRICK MURRAY: He knows that his weight is going to be an issue. Image has a lot to do with being president.

ROSE: Patrick Murray is a pollster at Monmouth University in New Jersey. He says Christie's weight was used against him during his first run for governor, in 2009.

(SOUNDBITE OF POLITICAL AD)

UNIDENTIFIED MAN: Christie threw his weight around as U.S. attorney and got off easy.

ROSE: And Murray says weight could be an issue again, if Christie seeks the Republican nomination for president in 2016, as he is widely expected to do.

MURRAY: That is something that the governor realizes that some voters will look at. And so he's taking charge of this situation as best he can right now.

ROSE: New Jersey voters interviewed at the Port Authority bus terminal, in Manhattan, seemed glad that the governor is trying to get healthier.

JOHN ANDRIOLI: He can't lose it on his own. I can't lose it on my own. He got it done - good.

ROSE: John Andrioli, of Lyndhurst, N.J., applauds Christie for having the weight-loss surgery, though he thinks Christie could be president without it.

ANDRIOLI: You look at Taft; he was huge. Some of our other presidents were huge. Teddy Roosevelt was huge. They were good presidents. It doesn't have to do with his weight. It's what is in the mind, and what is in his heart, and what he's going to do for the country.

ROSE: But William Howard Taft and Teddy Roosevelt didn't have to think about how they looked on TV.